Form and fill type packaging machines are commonly used for a variety of packaging applications. In such machines, a packaging material is typically unwound from a roll, formed into a tube around a mandrel, and the free edges are sealed together (e.g., to form a fin seal). The bottom end of the tube is then sealed together to form an end seal, often using a pair of heated jaws or clamps. As the seal is being formed, the items to be packaged are inserted (often dropped) into the package. As a result, the newly formed heat seal needs to have sufficient “hot tack” or “hot tack strength” to support the weight of the package contents. Thus, there remains a need for packaging materials that provide sufficient hot tack strength, even under rigorous manufacturing conditions. For some applications, there is also a need for such materials to be repulpable.